ZocdocAnswersWhy does my heart sometimes race when I first get up in the morning?

Question

Why does my heart sometimes race when I first get up in the morning?

I'm a 45-year-old woman and I don't take any medications except birth control. Sometimes when I get up in the morning, my heart rate is unusually fast. I often take my blood pressure in the morning, and it will be normal (under 120/80, although the diastolic is sometimes between 80 and 90 if I haven't been exercising regularly) but my pulse will be between 110 and 120. Most mornings, my resting pulse is between 70 and 80 beats per minute. When my pulse is fast, I don't feel faint or dizzy, but I do feel a little jittery. Typically my pulse settles back down to a normal rate within an hour or so. This doesn't occur frequently, maybe once or twice a month, but it concerns me. What are the possible reasons my pulse would be faster than usual first thing in the morning? I don't think it's happening any other time of the day.

Answer

A fast heart rate, just in the morning is an unusual complaint. Most people don't take their pulse unless they feel abnormal, so it may be more common than we know. A heart rate of 110 to 120 is fast. I can think of a couple possibilities. If you are a little dehydrated some mornings, and take your pulse just after you stand up, then you may be a little "orthostatic." What this means is that when you stand up, some of your blood falls down to your legs by gravity. Most of the time, your arteries squeeze down on the blood to maintain blood pressure. If you are dehydrated, the heart needs to speed up temporarily to maintain blood pressure. Another possibility is that you are having a supra-ventricular tachycardia (SVT), a type of heart arrhythmia. People that have this type of arrhythmia do feel jittery or generally unwell when their heart flips into this rhythm. The rhythm is also typically faster than 110-120. Finally, an SVT does not just happen in the morning, it can happen any time. i suggest that you schedule an appointment with your primary care physician. He or she can get an electrocardiogram done to see if you have any electrical abnormalities that would predispose you to this type of rhythm. If you do, then you will need referral to a electrophysiology specialist.

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